1. Field of the Invention
This invention relates generally to printed wiring boards and methods of making the same, and more particularly to a printed wiring board for a keyboard switch assembly and a method of making the same.
2. Description of the Prior Art
U.S. Pat. No. 3,796,843 to Durkee, et al. and assigned to the assignee of the present application discloses a keyboard switch assembly in which a complete X-Y matrix is provided with conductors on one side only of a printed wiring board by proportioning the switch elements so that certain of the conductors can extend under certain switch elements between respective terminal portions of other conductors.
In the fabrication of printed wiring boards for keyboard switch assemblies, such as that shown in the aforesaid Durkee, et al patent, it has been customary to provide switch contacts on the terminal portions of the copper conductors by gold plating over nickel in turn plated on the copper terminal portions, the nickel plating serving as a barrier between the copper and gold so as to inhibit migration of the gold into the copper at soldering temperatures. While such a construction provides entirely satisfactory switch contacts, it is obviously costly.
Further, even with the improved printed wiring board arrangement disclosed in the aforesaid Durkee, et al. patent, there are instances where it is desirable to provide connections between certain conductors which cannot be done without forming such connections on the reverse side of the board which in turn requires making connections through the board to the respective conductors thus adding appreciably to the overall cost of the board.
The fabrication of a printed wiring board by screen printing conductive ink traces or conductors on a surface of an insulator board is well known; however, it is difficult to make soldered connections to such conductive ink traces.